Well, a Church is not necessarily a 501c3...one can get a tax ID and a bank account without it. There are guidelines on the IRS website about that...IRS is clear that due to separation of church vs state, a Church is a Church without being 501c3. 501c3 has some perks naturally like corporate veil and all that.

OKay, I opened a can of worms greater than this thread, I apologize, back to the Ops original message.

the issue can only be resolved by Ecumenical Council and not by personal feelings of any bishop.

The non-Chalcedonians are so called because they don't accept the Council of Chalcedon (and the subsequent Councils). Some kind of recognition of all 7 Councils (though not necessarily all the canons thereof - Rome did not accept all canons of Chalcedon and remained in communion with the east) might be necessary for reunion to take place, but I don't believe another Ecumenical Council must be held to resolve the issue.

In the Middle East, there is a great deal of mixing, even in parishes, of EO and OO.

And Catholics too, unfortunately. In the Levant it is quite common for priests of both the EO and OO Patriarchates of Antioch to commune Catholics without any preconditions. This is also true of some of the Syrian clergy serving in Egypt under the Patriarchate of Alexandria.